It is customary in the communications industry to provide coils of strand material, which is referred to as wire and which typically includes a relatively small number of transmission media enclosed in a jacket, for installation purposes. Such a coil generally is provided in a container or carton which typically is made of corrugated fiberboard. The carton is used to prevent inadvertent unravelling of the coil of wire during storage and during handling.
In the prior art, there is disclosed a package comprising a carton and a coil of elongated strand material. The carton includes a pair of generally truncated conically shaped members, which are referred to as cones, projecting in opposite directions into a central open core of the coil of elongated strand material to provide support for the coil during handling and while the package of wound material is being unwound. The use of cones extending into the central core space of the wound strand material also prevents the loops of the strand material from becoming entangled during unwinding of the material from the carton.
Strand material, beginning from the core of the coil, is drawn or payed out through a feed or payout tube extending radially through the loops of the coil and through a wall panel of the carton. Such a payout arrangement generally is referred to as inner end payout. The packaging of wound material in cartons for inner end payout is known to the art and such packages are often referred to as non-reel types.
Along with the increasing use of such strand material unwound by inner end payout, there has arisen a need to provide an improved carton both to support and protect the coil during handling and use. Also important is that the carton have sufficient strength and suitable configuration such that a plurality of such cartons can be stacked safely one upon the other without breakage of the carton or damage to the coils of strand material stored therewithin.
In the past, packages of the so-called non-reel types have included a conventional corrugated fiberboard carton having separate cones inserted into the center open core of the coil of strand material. Although separate cones also facilitate the unwinding of the strand material from the interior of the coil to the outside, it has been found that separate cone inserts complicate the packaging operation and increase the cost of the package.
In a more recently introduced package is disclosed a carton which package includes four wall panels which are joined end-to-end by hinge connections and which provide the perimeter of an assembled carton. Inner and outer closure flaps are hingedly connected to each of opposed side edges of the wall panels. Tabs are hinged to the center of a free side edge of each of the closure flaps, each of the tabs being generally tapered. Open ended slots are provided in the free end of each tab of two sets of the tabs which are associated with outer ones of the closure flaps. Each of the open ended slots extends from a free edge of its associated tab to a point spaced from a line of connection of the tab to its adjacent associated outer closure flap. Internal slots are provided in the tabs which extend from the inner closure flaps. The internal slots also extend along the tabs but begin inwardly of the free ends of the tabs and extend across the lines of connection of the tabs to their adjacent associated inner closure flaps and terminate in these inner flaps. When the tabs extending from the inner closure flaps are folded along their connection lines, portions of the internal slots are located in the tabs and portions in the inner closure flaps.
In the assembly of the last mentioned carton, ends of end ones of the wall panels are attached together to provide a perimeter of the carton. Afterwards, two of the inner closure flaps are folded inwardly and tabs associated therewith abut each other as they are caused to project into the center of the volume defined partially by the four wall panels. Also portions of the internal slots which are disposed in the inner closure flaps are aligned. Then outer closure flaps and associated tabs are folded inwardly over the inner closure flaps. when a pair of the folded tabs of two of the outer closure flaps abut one another, they are inserted into the internal slots of the previously closed inner closure flaps. As aligned internal slots of each pair of abutting inner closure flaps receive abutting tabs of two outer closure flaps, walls which define the internal slots engage the outer walls of the abutting tabs. The tabs become interlocked in a perpendicular relationship with tabs associated with the inner closure flaps to form a cone extending inwardly of the carton. A package is formed by inserting a coil of strand material into the carton which is formed in such a manner that an open center portion of the coil is disposed over the cone. Then the inner and outer closure flaps which extend from opposite sides of the wall panels are folded over into a closed position. Another cone is formed and extends into the open core of the coil.
Several problems relating to the just-described package have surfaced. The carton is somewhat difficult to manufacture. Usually, a blank which has dimensions equal to those of the developed carton including the tabs is provided. Then the blank is cut by a punch and die apparatus to provide a planar, formed blank which includes wall panels and tabs extending therefrom. Afterwards, the blank is scored to provide hinged connections in the form of fold lines between wall panels and flaps and between the flaps and the tabs.
Because of the tabs extending from end ones of the wall panels in the blank, there are insufficient lengths of edge surfaces along outer edges of the flaps and panels to square-up accurately the formed blank for the scoring step. As a result, the carton which is assembled using those scored lines may be out of square. If so, such cartons are difficult to arrange in a stable stack. The scrap rate for blanks formed in this manner has been at an unacceptable level.
Also, because of a lack of tabs which lock positively within notches or slits, carton flaps are not adequately secured into desired positions. Hence, adhesively-backed tape needs to be applied across the flaps in order to maintain the configuration of the assembled carton subsequent to the insertion of the coil of strand material.
What is needed and what seemingly has not been provided by the prior art is a package including a carton which is easily manufactured with a scrap rate reduced substantially over that of the prior art and which in assembled form is stackable. Desirably, the sought after carton includes an improved locking arrangement which is effective to hold the carton together in its assembled, closed configuration without the use of tape. Also, the sought after carton should compare favorably with presently available cartons in cost and should provide at least all the features for the coil of strand material to be inserted therein as does the prior art carton.